[Test] Excercise shutdown more reliably in snapshot stress IT (#132909)

See title

Author: ywangd

server/src/internalClusterTest/java/org/elasticsearch/snapshots/SnapshotStressTestsIT.java

@@ -1201,10 +1201,10 @@ private void startNodeRestarter() {
         private void startNodeShutdownMarker() {
             enqueueAction(() -> {
                 boolean rerun = true;
-                if (usually()) {
-                    return;
-                }
                 try (TransferableReleasables localReleasables = new TransferableReleasables()) {
+                    if (usually()) {
+                        return;
+                    }
                     if (localReleasables.add(blockFullClusterRestart()) == null) {
                         return;
                     }